Broadcast recording system, recording apparatus, broadcasting apparatus, and recording program for saving storage space of recording medium used for recording contents

ABSTRACT

An adding unit  14  of a broadcasting apparatus  11  attaches entry information to a content to be broadcast. The entry information specifies a content that is identical to the content to be broadcast out of a plurality of contents available for distribution by a distributing apparatus  12 . A sending unit  15  of the broadcasting apparatus  11  broadcasts the content with the entry information attached thereto. An entry information recording unit  106  of a recording apparatus  30  records the entry information that is attached to the received content to a hard disk  104 , and a requesting unit  107  requests the distributing apparatus  12  to distribute the content specified by the recoded entry information. A content distributing unit  21  of the distributing apparatus  12  receives the distribution request, and distributes the requested content to the recording apparatus  30 . The recording apparatus  30  plays back the distributed content.

TECHNICAL FIELD

The present invention relates to a broadcast recording system forrecording broadcast contents for time-shift viewing. More particularly,the present invention relates to technology to reduce the storage spaceof a recording medium used to record the contents.

BACKGROUND ART

In addition to real-time viewing, viewers of TV broadcasts are allowedto record contents with a recording apparatus for the purpose oftime-shift viewing at their convenience.

JP Translation of International Application Publication No. 2002-521978(page 13, FIG. 1) discloses technology for recording contents to arecording medium such as a hard disk in digital form and for playback ofrecorded contents.

FIG. 1 is a view showing the structure of a conventional recordingapparatus 100. The recording apparatus 100 is composed of functionalblocks of a receiving unit 101, a switch 102, an output unit 103, a harddisk 104, and a CPU 105.

The receiving unit 101 converts received contents to MPEG2 (MovingPicture Experts Group phase 2) streams, and outputs the resulting MPEG2streams. For example, when video input is an analog signal according tothe NTSC (National Television System Committee) standard, a tunerprovided in the receiving unit 101 tunes for a target content, and anMPEG encoder that is also provided in the receiving unit 101 convertsthe content to an MPEG2 stream and outputs the resulting stream. Inanother example, when video input is a digital signal is an MPEG2transport stream (hereinafter simply referred to as TS) multiplexed withan MPEG2 stream containing a content, a digital tuner provided in thereceiving unit 101 extracts a target MPEG2 stream from the inputted TS,and outputs the extracted MPEG2 stream.

The switch 102 receives, in recording operations, a content to berecorded from the receiving unit 101 and outputs the content to the harddisk 104. In playback operations, the switch 102 reads a content to beplayed back from the hard disk 104 and outputs the read content to theoutput unit 103.

The output unit 103 acquires an MPEG2 stream and outputs the acquiredMPEG2 stream to a television set connected to the recording apparatus100. In the case where the television set is in compliance with the NTSCstandard, the output unit 103 outputs the content after decoding it toan NTSC signal.

The hard disk 104, in recording operations, records an MPEG2 streaminputted from the switch 102 to a storage area. In playback operations,the hard disk 104 reads an MPEG2 stream that corresponds to a contentrequested for playback, and outputs the read MPEG2 stream to the switch102.

The CPU 105 controls operations of the receiving unit 101, the switch102, the output unit 103, and the hard disk 104 in order to carry outrecording or playback of a requested content according to a useroperation or to a recording schedule programmed in advance by the user.When recoding of a content is requested by a user operation or aprogrammed recording schedule, the CPU 105 controls overall operations,so that the receiving unit 101 acquires the requested content, theswitch 102 outputs the MPEG2 stream inputted from the receiving unit 101to the hard disk unit 104, and the hard disk 104 records the inputtedMPEG2 stream.

When playback of a content is requested by a user operation, the CPU 105controls overall operations, so that the hard disk 104 reads an MPEG2stream corresponding to the requested content, the switch 102 outputsthe MPEG2 stream inputted from the hard disk 104 to the output unit 103,and the output unit 103 decodes the inputted MPEG2 stream to audio andvideo signals and then outputs the resulting signals to an externaltelevision set. There may be a case where the recording apparatus isrequested to carry out playback of a content recorded in the hard disk104 while recording another content. In this case, the CPU 105 controlsthe recording and the playback in parallel, so that the switch 102outputs an MPEG2 stream inputted from the receiving unit 101 to the harddisk unit 104, and concurrently outputs an MPEG2 stream inputted fromthe hard disk 104 to the output unit 103.

The recording apparatus having the above-stated structure is capable ofrecording a content requested by a user, and playback of a recordedcontent any time at user's convenience.

Recently, recording apparatuses with a large-capacity recording mediumsuch as a hard disk and a DVD-RAM are now in common use. Such arecording apparatus is capable of recording contents in digital form,which is bulky but of high image quality. Users of those recordingapparatuses tend to record a numbers of contents for the purpose oftime-shift viewing. In order to meet the users' demand for recording alarge number of contents, it is desired to increase the storage capacityof recording apparatuses.

Unfortunately, however, increase in the storage capacity inevitablyinvolves increase in the cost. Yet, it is undesirable to record contentsat higher data compression ratio, which leads to another problem ofdegradation in image quality.

DISCLOSURE OF THE INVENTION

The present invention is made in view of the above problems, and has afirst object to provide a broadcast recording system capable of storingcontents to a recording medium using a smaller storage space than in theprior art.

Further, it is a second object of the present invention to provide arecording apparatus and a broadcasting apparatus that are suitable foruse in the broadcast recording system stated above.

Still further, it is a third object of the present invention to providea recording program with which a computer runs to realize the functionsof the recording apparatus stated above.

To achieve the objects stated above, the present invention provides abroadcast recording system having a broadcasting apparatus, adistributing apparatus, and a recording apparatus. The broadcastingapparatus includes: an attaching unit operable to attach to a broadcastcontent that is for broadcasting and that corresponds to a specific oneof a plurality of contents each composed at least of video and audiodata, entry information specifying a distribution content that iscomposed of video and audio data and identical to the specific contentwith respect to a substance of the video and audio data out of aplurality of distribution contents available for distribution by adistributing apparatus; and a broadcasting unit operable to broadcastthe broadcast content with the attached entry information. The recordingapparatus includes a receiving unit operable to receive the broadcastcontent with the attached entry information from the broadcastingapparatus; an entry information recording unit operable to record theentry information attached to the received broadcast content to astorage area; and a requesting unit operable to request the distributingapparatus to distribute the distribution content specified by therecorded entry information. The distributing apparatus distributes thespecified distribution content to the recording apparatus in response tothe distribution request from the requesting unit. The recordingapparatus receives, after broadcasting of the broadcast content that isidentical to the specific content with respect to the substance of thevideo and audio data, the distribution content that is identical to thespecific content with respect to the substance of the video and audiodata and plays back the received distribution content.

With the structure stated above, when broadcasting a broadcast contentthat corresponds to a predetermined content to a recording apparatus,the broadcasting apparatus broadcasts entry information together withthe broadcast content. The entry information is to be used by therecording apparatus to receive a distribution content corresponding tothe predetermined content. The recording apparatus records the entryinformation that is attached to the broadcast content. At a later time,the recording apparatus receives, using the recorded entry information,distribution of the distribution content that corresponds to thepredetermined content. Consequently, the user can view the distributioncontent that is identical to the broadcast content with respect to asubstance of the video and audio data.

That is to say, the recording apparatus receives from the distributingapparatus, a distribution content that corresponds to a broadcastcontent with a substantially equal image quality. With this arrangement,the user can view a content that corresponds to a broadcast contentwithout any loss of image quality while saving the storage space of therecording apparatus that would otherwise be used to actually record thebroadcast content.

To achieve the objects stated above, in another aspect of the presentinvention provides a recording apparatus having: a receiving unitoperable to receive, from a broadcasting apparatus for broadcastingbroadcast contents each of which is for broadcasting together with entryinformation attached thereto and corresponds to a content composed atleast of video and audio data, a broadcast content that is composed ofvideo and audio data and identical to a specific one of the contentswith respect to a substance of the video and audio data together withattached entry information specifying a distribution content that iscomposed of video and audio data and identical to the specific contentwith respect to a substance of the video and audio data out of aplurality of distribution contents available for distribution by adistributing apparatus; an entry information recording unit operable torecord the entry information attached to the received broadcast contentto a storage area; and a requesting unit operable to request thedistributing apparatus to distribute the distribution content specifiedby the recorded entry information. The recording apparatus plays backthe distribution content distributed by the distributing apparatus inresponse to the distribution request.

With the structure stated above, the recording apparatus records entryinformation attached to a broadcast content provided throughbroadcasting. At a later time, the recording apparatus uses the recordedentry information so as to receive from the distributing apparatus, adistribution content that is identical to the broadcast content withrespect to a substance of the video and audio data. Consequently, theuser is allowed to view the distribution content at a later time.

That is to say, the storage space of the recording apparatus issignificantly saved in comparison with the case where the broadcastcontent is actually recorded. Further, even when the user makes arecordation request some time after the start of broadcasting of abroadcast content, the recording apparatus records the entryinformation, and receives a distribution content from the distributingapparatus using the recorded entry information. Consequently, the useris allowed to view the distribution content from the beginning of thecontent.

Here, the broadcast content and the distribution content that correspondto the specific content may be all identical as a copyrighted work, andat least one of the broadcast content and the specific content maydiffer from the specific content with respect to an image quality.

With the structure stated above, the recording apparatus can receive adistribution content of which substance as a copyrighted work isidentical to a broadcast content although the image quality isdifferent.

Here, the recording apparatus may further have: a judging unit operableto judge whether to record the received broadcast content; and a contentrecording unit operable to record the received broadcast content to thestorage area when the judging unit judges to record the broadcastcontent.

With the structure stated above, the broadcast content is also recordedin addition to the entry information.

Consequently, when either of a broadcast content and a distributioncontent is preferable to the other in some regard, the recordingapparatus allows the user to view whichever content is preferable.

Here, the judging unit may judge not to record the received broadcastcontent when the entry information is attached, and judge to record thereceived broadcast content when the entry information is not attached.

With the structure stated above, when failing to acquire entryinformation attached to a broadcast content, the recording apparatusrecords the broadcast content to the storage area.

That is to say, when duly acquiring entry information attached to abroadcast content, the recording apparatus does not record the broadcastcontent, thereby saving the storage space. Yet, when failing to acquireentry information attached to a broadcast content, the recordingapparatus records the broadcast content so as to ensure that the contentis available for the user to view at a later time.

Here, the entry information may further include information showingimage quality of the distribution content specified by the entryinformation. The judging unit may judge to record the received broadcastcontent when image quality of the received broadcast content is higherthan the image quality shown by the entry information, and judge not torecord the received broadcast content when the image quality of thereceived broadcast content is lower.

With the structure stated above, the recording apparatus compares abroadcast content broadcast from the broadcasting apparatus with adistribution content to be distributed by the distributing apparatus.When the broadcast content is of better image quality, the recordingapparatus records the broadcast content. Consequently, the user isallowed time-shift viewing of the broadcast content that is of goodimage quality. On the other hand, when the distribution content is ofbetter image quality, the recording apparatus records entry information.Consequently, the storage space that would otherwise be used to recordthe broadcast content is saved, and yet the user is allowed to view thedistribution content that is of good image quality at a later time.

Here, the judging unit may judge to record the received broadcastcontent when a free storage space remaining in the storage area isgreater than a storage space required for recording the broadcastcontent, and judge not to record the received broadcast content when thefree storage space is smaller.

With the structure stated above, when enough storage space is left torecord a broadcast content, the recording apparatus records thebroadcast content.

Consequently, when a broadcast content is preferable to a distributioncontent in some regard, for example in the image quality, the broadcastcontent is recorded as long as the available storage capacity permits.In addition, even if there is not enough storage space to store thebroadcast content, the distribution content is still acquired forviewing although the distribution content is of lower image quality.

Here, the entry information recording unit may not record the entryinformation when the broadcast content is judged to be recorded.

With the structure stated above, it is avoided to redundantly store botha broadcast content and entry information, so that the storage space tobe used is minimized.

Here, the entry information recording unit may record to the storagearea, the entry information attached the broadcast content beingrecorded by the content recording unit when a free storage space of thestorage area falls short to record entirety of the broadcast content.

With the structure stated above, even if the storage space runs out inthe middle of recordation of a broadcast content, the user is stillallowed to view the content as the recording apparatus receives adistributing content using the recorded entry information.

Here, the recording apparatus may further have: a content recording unitoperable to record the received broadcast content to the storage area;and a content deleting unit. The entry information may further includeinformation showing a release date-time on which the distributioncontent starts to be available for distribution, and the contentdeleting unit may delete the broadcast content recorded by the contentrecording unit from the storage area on or after the release date-time.

With the structure stated above, the recording apparatus records abroadcast content in addition to entry information in the case where itis a while until a release date/time of a corresponding distributioncontent and thus the distribution content is not yet available for theon-demand distribution service at the time of the broadcasting.Consequently, the user is allowed to view the recorded broadcast contentuntil the release date/time comes. In addition, since the recordingapparatus deletes the recorded broadcast content on or after the releasedate/time, the storage space that would otherwise be kept occupied bythe broadcast content is saved.

Consequently, the recording apparatus is capable of saving the storagespace at an earliest possible time, while eliminating the undesirablepossibility that the user is unable to see neither a broadcast contentnor a distribution content.

Here, the recording apparatus may further have a content recording unitoperable to record to the storage area, the distribution content that isdistributed by the distributing apparatus in response to thedistribution request. The entry information may further includeinformation showing an expiry date-time after which the distributioncontent is no longer available for distribution. The requesting unit mayrequest distribution of the distribution content prior to the expirydate-time.

With the structure stated above, the recording apparatus receives andrecords a distribution content before the distributing apparatusterminates the distribution service for the content. Consequently, whilesaving the storage space as long as possible, the recording apparatusmanages to eliminate the possibility that the user can not view adesired content because the recording apparatus only stores entryinformation of the content and a corresponding distribution content isno longer available due to the expiry of the distribution service.

Here, the recording apparatus may further have an entry informationrequesting unit operable to request the distributing apparatus todistribute the entry information when any information item is missing inthe entry information attached to the received broadcast content. Theentry information recording unit may record to the storage area, theentry information that is distributed from the distributing apparatus inresponse to the request from the entry information requesting unit.

With the structure stated above, the recording apparatus newly acquiresentry information when failed to correctly acquire the entryinformation.

Consequently, the recording apparatus is provided with a greater numberof opportunities to acquire entry information, so that the chances ofsaving the storage space increases.

Here, the receiving unit may receive from the broadcasting apparatus, abroadcast content corresponding to a first content and with first entryinformation attached thereto. The first entry information specifies adistribution content that is composed of video and audio data andidentical to the first content with respect to a substance of the videoand audio data. The receiving unit may further receive, after the entryinformation recording unit records the first entry information, abroadcast content that corresponds to a second content and that isbroadcast with second entry information attached thereto from anotherbroadcasting apparatus during the broadcasting of the broadcast contentcorresponding to the first content. The second entry informationspecifies a distribution content that is composed of video and audiodata and identical to the second content with respect to a substance ofthe video and audio data. The entry information recording unit mayrecord the first entry information to the storage area when thereceiving unit receives the broadcast content to which the first entryinformation is attached, and further record the second entry informationto the storage area when the receiving unit receives the broadcastcontent to which the second entry information is attached.

With the structure stated above, the recording apparatus records firstentry information attached to a broadcast content, which eliminates theneed to record the broadcast content at all times throughout thebroadcasting hours. Consequently, the recording apparatus is capable ofrecording second entry information that is attached to another broadcastcontent on another channel although the broadcasting hours of the twobroadcast contents overlap.

Since entry information is recorded only within a time period shorterthan the broadcasting hours, a recording apparatus without a pluralityof tuners is still capable of sequentially selecting a broadcast channeland records entry information attached to a broadcast content on eachchannel. At a later time, the recording apparatus receives distributioncontents using each piece of stored entry information. Consequently, theuser is allowed to view playback of a plurality of contents that areconcurrently broadcast, so that the user's convenience increases.

Here, the broadcasting apparatus may broadcast a broadcast contentmultiplexed with another broadcast content. One of the broadcastcontents corresponds to a first content and with first entry informationattached thereto. The first entry information may specify a distributioncontent that is composed of video and audio data and identical to thefirst content with respect to a substance of the video and audio data.The other broadcast content corresponds to a second content and withsecond entry information attached thereto. The second entry informationspecifies a distribution content that is composed of video and audiodata and identical to the second content with respect to a substance ofthe video and audio data. The information recording unit may record thefirst entry information and the second entry information to the storagearea.

With the structure stated above, the recording apparatus receives abroadcast wave into which a plurality of broadcast contents ismultiplexed, and stores entry information of each of the multiplexedbroadcast contents.

Consequently, even without an advanced capability of recording aplurality of broadcast contents in parallel, the recording apparatus isstill capable of recording a plurality of pieces of entry information,so that corresponding distribution contents may be later received forviewing.

To achieve the objects stated above, yet another aspect of the presentinvention provides a broadcasting apparatus having: an attaching unitoperable to attach to a broadcast content that is for broadcasting andthat corresponds to a specific one of a plurality of contents eachcomposed of at least video and audio data, entry information specifyinga distribution content that is composed of video and audio data andidentical to the specific content with respect to a substance of thevideo and audio data out of a plurality of distribution contentsavailable for distribution by a distributing apparatus; and abroadcasting unit operable to broadcast the broadcast content with theattached entry information.

With the structure stated above, the broadcasting apparatus provides toa recording apparatus, a broadcast content corresponding to apredetermined content together with entry information. The entryinformation is to be used by the recording apparatus to receive adistribution content that corresponds to the predetermined content.

Consequently, the recording apparatus which receives a content broadcastfrom the broadcasting apparatus is allowed to store entry informationattached to the broadcast content. Using the entry information, therecording apparatus can later receive a distribution contentcorresponding to the broadcast content, so that the user can view thereceived distribution content. Further, since the distributing apparatusdistributes a distribution content which is substantially identical to abroadcast content with respect to a substance of the video and audiodata and image quality, the storage space of the recording apparatus issignificantly saved in comparison with the case where the recordingapparatus records all the broadcast contents.

Here, the attaching unit may further include: a distribution judgingsubunit operable to judge whether the distribution content correspondingthe specific content is available for distribution by the distributingapparatus; and an entry information generating subunit operable, whenthe distribution judging subunit judges in affirmative, to generate theentry information specifying the distribution content corresponding thespecific content, and attach the generated entry information to thebroadcast content.

With the structure stated above, when broadcasting a broadcast contentto which a corresponding content is available for distribution by thedistributing apparatus, the broadcasting apparatus attaches entryinformation to the broadcast content.

To achieve the objects stated above, yet another aspect of the presentinvention provides a recording program for having a computer perform: areceiving step of receiving, from a broadcasting apparatus forbroadcasting broadcast contents each of which is for broadcastingtogether with entry information attached thereto and corresponds to acontent composed at least of video and audio data, a broadcast contentthat is composed of video and audio data and identical to a specific oneof the contents with respect to a substance of the video and audio datatogether with attached entry information specifying a distributioncontent that is composed of video and audio data and identical to thespecific content with respect to a substance of the video and audio dataout of a plurality of distribution contents available for distributionby a distributing apparatus; an entry information recording step ofrecording the entry information attached to the received broadcastcontent to a storage area; a requesting step of requesting thedistributing apparatus to distribute the distribution content specifiedby the recorded entry information; and a playback step of playing backthe distribution content distributed by the distributing apparatus inresponse to the distribution request.

With the structure stated above, the recording apparatus is allowed torecord entry information attached to a broadcast content that isbroadcast from the broadcasting apparatus, and uses, at a later time, toreceive distribution of a corresponding distribution content.Consequently, the user can view the distribution content that isidentical to the broadcast content with respect to a substance of thevideo and audio data.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view showing the structure of a conventional recordingapparatus;

FIG. 2 is a view showing the configuration of a broadcast recordingsystem 1 according to an embodiment 1 of the present invention;

FIG. 3 is a view showing the data structures of entry informationaccording to the embodiment 1 and a TS 300 into which the entryinformation is multiplexed;

FIGS. 4A and 4 b are views showing the data structures of messagesgenerated by a request generating subunit 121;

FIG. 5 is a view showing the data structure of a distributioninformation table stored in a distribution content accumulating unit 23;

FIG. 6 is a view showing the structure of a recording apparatus 30according to the embodiment 1 of the present invention;

FIGS. 7A, 7B, and 7C are views showing the data structure of entryinformation acquired by an entry information recording unit 106 alongwith specific examples of the entry information;

FIG. 8 is a view showing the flow of operations performed by thebroadcast recording system 1 for broadcasting a content through thebroadcast service;

FIG. 9 is a view showing the flow of operations performed by thebroadcast recording system 1 for recording a content that is broadcastthrough the broadcast service;

FIG. 10 is a view showing the flow of another example of operationsperformed by the broadcast recording system 1 for recording a contentthat is provided through the broadcast service;

FIG. 11 is a view showing the flow of operations performed by therecording apparatus 30 for managing recorded contents;

FIG. 12 is a view showing the flow of operations performed by therecording apparatus 30 when the user views a recorded content;

FIG. 13 is a view showing the configuration of a broadcast recordingsystem 2 according to an embodiment 2 of the present invention;

FIG. 14 is a view showing the structures of a television broadcaststation 40 and a content distribution center 60 according to theembodiment 2 of the present invention;

FIG. 15 is a view showing the data structures of entry informationaccording to the embodiment 2 and of an NTSC signal 401 into which theentry information is superimposed;

FIG. 16 is a view showing the details of a packet generated by a requestgenerating subunit 210;

FIG. 17 is a view showing the structure of a recording apparatus 50according to the embodiment 2 of the present invention;

FIG. 18 is a view showing the flow of operations performed by thebroadcast recording system 2 for recording a content that is providedthrough the broadcast service; and

FIG. 19 is a view showing the flow of the operations performed by thebroadcast recording system 2 to provide a content through the on-demanddistribution service.

BEST MODE FOR CARRYING OUT THE INVENTION

The following describes a broadcast recording system as an embodimentaccording to the present invention, with reference to the accompanyingdrawings.

Embodiment 1

Overview

A broadcast recording system 1 according to an embodiment 1 of thepresent invention receives contents that are broadcast or distributedon-demand via a cable television (hereinafter, referred to as “CATV”)cable. Users who subscribe to the CATV are allowed to record receivedcontents with a recording apparatus.

Each broadcast content is attached an identifier of a correspondingcontent, which is used to request on-demand distribution of thatcontent. The recording apparatus may record an identifier without anactual content. To play back the content, the recording apparatusrequests distribution of the content using the identifier so as toreceive the content. With this arrangement, the recording apparatussaves a significant amount of the storage space that would otherwise beused to record actual contents.

Structure

1.1 System Configuration

FIG. 2 is a view showing the configuration of the broadcast recordingsystem 1 according to the embodiment 1 of the present invention.

The broadcast recording system 1 is composed of a broadcast station 10and recording apparatuses 30. Each recording apparatus is connected tothe broadcast station 10 via the CATV cable.

The broadcast station 10 provides contents through two types ofservices. One is a broadcast service to provide contents at scheduledtimes according to a predetermined broadcast timetable. The other is anon-demand service to provide, in response to a distribution request froma recording apparatus 30, the requested content to the recordingapparatus 30 that issued the distribution request. The broadcast station10 provides each content through the on-demand service only afterbroadcasting a corresponding content through the broadcast service.

For the sake of convenience, this specification hereinafter referscopyrighted works that are identical with respect to the substance asone and the same content. That is to say, when a content to be broadcastand a content to be distributed are identical with respect to thesubstance as a copyrighted work, the two contents are regarded as oneand the same content irrespective of difference that may present incommercial messages inserted, the resolutions, and the bit rates.

Each recording apparatus 30 specifically is an HDD recorder with abuilt-in CATV tuner and located at home of a user being a CATVsubscriber. Each recording apparatus 30 receives contents from thebroadcast station 10 via the CATV cable through the broadcast service aswell as the on-demand service, and records and/or plays back thereceived contents.

1.2 Broadcast Station 10

Hereinafter, description is given in detail to the broadcast station 10.

The broadcast station 10 is composed of a broadcasting apparatus 11 forproviding contents through the broadcast service, and a: distributingapparatus 12 for providing contents through the on-demand service.

The broadcasting apparatus 11 includes function blocks of a broadcastcontent accumulating unit 13, an adding unit 14, and a sending unit 15,and broadcasts video, audio, and control data of a target contentaccording to the broadcast timetable, by multiplexing the data into a TSin compliance with the MPEG2 standard. In the case where the targetcontent is permitted to be later distributed from the distributingapparatus 12, the broadcasting apparatus 11 additionally multiplexesentry information used by the distributing apparatus 12 to specify thecontent, and broadcasts the resulting TS.

The broadcast content accumulating unit 13 is a large-capacity storagedevice that accumulates contents to be broadcast through the broadcastservice in MPEG2 streams. Here, each content is accumulated withcommercial messages inserted thereto, and thus in the ready state forbroadcasting without any further processing.

The adding unit 14 includes functional blocks of a distribution checkingsubunit 16, an information generating subunit 17, and a multiplexingsubunit 18. Prior to broadcasting a content that is permitted to bedistributed through the on-demand service, the adding unit 14additionally multiplexing entry information of the target content intothe TS.

The distribution checking subunit 16 informs a distribution informationpresenting unit 24 of the distributing apparatus 12 about a broadcastingdate/time of a content to be broadcast, and receives information aboutwhether a content identical to the content to be broadcast is permittedto be distributed through the on-demand service On receiving informationthat on-demand distribution of the content is permitted, thedistribution checking subunit 16 also receives a content ID, a releasedate/time, and an expiry date/time of the content from the distributioninformation presenting unit 24, and outputs the received information tothe information generating subunit 17.

The information generating subunit 17 generates entry information with alater described data structure using the information received from thedistribution checking subunit 16.

The multiplexing subunit 18 generates a TS 300 to be broadcast from thesending unit 15. The TS 300 is generated by multiplexing the MPEG2stream read from the broadcast content accumulating unit 13 with theentry information generated by the information generating subunit 17.

The sending unit 15 sends the TS outputted from the multiplexing subunit18 via the CATV cable according to the predetermined broadcasttimetable.

FIG. 3 is a view showing the data structures of entry informationaccording to the embodiment 1 and the TS 300 into which the entryinformation is multiplexed.

The TS 300 is generated by multiplexing an MPEG2-TS header 301 which isthe control information for the TS, a data stream 302 containing theentry information, and an MPEG2 stream 303 containing video and audiodata of the content.

The data stream 302 includes a data header 304 and the entry informationthat is composed of a content ID 305, release date/time information 306,and expiry date/time information 307.

The content ID 305 is an identifier for the distributing apparatus 12 touniquely identify a content that is identical to the one multiplexed inthe TS. The release date/time information 306 shows a date/time at whichthe distributing apparatus 12 starts the on-demand service for thecontent identified by the content ID 305. The expiry date/timeinformation 307 shows a date/time at which the distributing apparatus 12ends the on-demand service for the content identified by the content ID305.

The data stream 302 is transmitted in such a manner that the entryinformation is repeatedly transmitted during the broadcasting of thecontent. Consequently, the entry information may be extracted from theTS at any intended time during the broadcasting of the content.

The MPEG-2 TS header and the MPEG2 stream are well-known in the artdefined in the MPEG2 standard, and thus description thereof is omittedhere.

The distributing apparatus 12 is composed of a content distributing unit21, an entry information distributing unit 22, a distribution contentaccumulating unit 23, and a distribution information presenting unit 24.

The content distributing unit 21 receives a viewing request messageshown in FIG. 4A from a recording apparatus 30, reads a contentspecified by a content ID included in the viewing request message, anddistributes the read content to the recording apparatus 30 being therequest source.

The entry information distributing unit 22 receives additionalinformation acquisition message shown in FIG. 4B, searches adistribution information table shown in FIG. 5 for a content ID includedin the additional information acquisition message to acquire acorresponding piece of release date/time information and expirydate/time information, and transmits the acquired information to therecording apparatus 30 that issued the request.

The distribution content accumulating unit 23 is a large-capacityrecording device storing contents in MPEG2 streams available foron-demand distribution. The distribution content accumulating unit 23also stores the distribution information table in the storage area.

FIG. 5 is a view showing the data structure of the distributioninformation table stored in the distribution content accumulating unit23. The distribution information table contains as many pieces ofdistribution information as the contents available for on-demanddistribution.

Each piece of distribution information is in one-to-one correspondencewith a different one of the distribution contents, and is composed of abroadcast date/time, a content ID, a release date/time, and an expirydate/time of a corresponding content. The broadcast date/time shows thedate/time at which a broadcast content identical to the correspondingcontent is broadcast by the broadcasting apparatus 11. The content ID isan identifier that uniquely identifies the corresponding content. Therelease date/time and the expiry date/time show the starting date/timeand the ending date/time of a period during which the correspondingcontent is available for on-demand distribution. Note the in the casewhere the corresponding content has been made available for on-demanddistribution already, the release date/time is not specified. Further,the expiry date/time is not specified in the case where there is noexpiry for the period during which the corresponding content may bedistributed.

The distribution information presenting unit 24 receives from thedistribution checking subunit 16, the broadcast date/time of a contentto be broadcast, and searches the distribution information table formatching distribution information that contains the received broadcastdate/time. When finding matching distribution information, thedistribution information presenting unit 24 informs the distributionchecking subunit 16 that the content to be broadcast is available foron-demand distribution, and outputs the content ID, the releasedate/time and the expiry date/time shown by the matching distributioninformation to the distribution checking subunit 16.

1.3 Recording Apparatus 30

Next, description is given to the structure of a recording apparatus 30.Note that all of the recording apparatus 30 are similar to each other instructure.

FIG. 6 is a view showing the structure of the recording apparatus 30according to the embodiment 1 of the present invention.

The recording apparatus 30 is composed of a receiving unit 101, a switch102, an output unit 103, a hard disk 104, a CPU 105, an entryinformation recording unit 106, and a requesting unit 107. Note thatthose components denoted by the same reference numerals as in theconventional recording apparatus 100 are similar to the correspondingcomponents, and thus the description thereof is omitted.

The receiving unit 101 is a functional block for receiving a TS that isbroadcast or distributed from the broadcast station 10. Specifically,the receiving unit 101 is composed of a CATV tuner 108 and a TS decoder109.

The CATV tuner 108 selectively extracts from signals received via theCATV cable, a TS on a channel specified or programmed in advance by auser operation.

The TS decoder 109 demultiplexes the TS acquired by the CATV tuner 108so as to separate an MPEG2 stream and a data stream, and then outputsthe MPEG2 stream to the switch 102 and the data stream to the entryinformation recording unit 106.

Specifically, the output unit 103 is an MPEG2 decoder 110. On receivingthe content that is encoded to the MPEG2 stream from the switch 102, theoutput unit 103 decodes the MPEG2 stream to an NTSC signal, and outputsthe resulting NTSC signal to the television set.

The entry information recording unit 106 includes an ID acquiringsubunit 118, a release date/time acquiring subunit 119, and an expirydate/time acquiring subunit 120. On receiving the data stream separatedfrom the TS by the TS decoder 109, the ID acquiring subunit 118, therelease date/time acquiring subunit 119, and the expiry date/timeacquiring subunit 120 extract the content ID, the release date/time, andthe expiry date/time from the data stream, respectively. As a result,the entry information recording unit 106 acquires the entry informationshown in FIG. 7A. FIGS. 7A, 7B, and 7C show the data structure of theentry information acquired by the entry information recording unit 106along with specific examples of the entry information.

Further, the entry information recording unit 106 informs a recordationjudging unit 111 as to whether each of the content ID, releasedate/time, and expiry date/time has been acquired, and records the entryinformation to the hard disk 104 according to instructions from therecordation judging unit 111.

The requesting unit 107 is composed of a request generating subunit 121and a CATV modem 122, and issues to the distributing apparatus 12 arequest for on-demand distribution of a content and a request fortransmission of entry information.

The request generating subunit 121 generates a viewing request messageshown in FIG. 4A, and then the CATV modem 122 transmits the generatedmessage to the distributing apparatus 12 via the CATV cable. The requestgenerating subunit 121 performs the above operation at the time ofplayback of a content of which entry information is recorded in the harddisk 104 without the content itself, or in response to an instructionfrom an expiry date/time monitoring subunit 117 that monitors expirydates/times.

Further, in response to an instruction from the recordation judging unit1 to acquire entry information, the request generating subunit 121acquires a content ID corresponding the entry information to beacquired, generates an additional information acquisition message shownin FIG. 4B. Subsequently, the CATV modem 122 converts the generatedmessage to an output signal, and transmits the resulting signal to thedistributing apparatus 12 via the CATV cable. Note that the requestgenerating subunit 121 may acquire the content ID directly from theentry information recording unit 106, or by reading a content ID writtento the hard disk 104 by the entry information recording unit 106.

The CPU 105 controls each functional block so as to control recordationor playback of a content.

In response to a user operation requesting playback of a content, theCPU 105 attempts to acquire the requested content from the hard disk104. In the case where the hard disk 104 stores an MPEG2 stream of therequested content, the CPU 105 instructs to read the MPEG2 stream, andcontrols the switch 102 and the MPEG2 decoder 110 so as to play back thecontent.

On the other hand, in the case where the hard disk 104 only stores entryinformation of the requested content without the MPEG2 stream, the CPU105 controls the hard disk 104 to output the entry information to therequesting unit 107, and instructs the requesting unit 107 to transmit aviewing request message. The CPU 105 further controls the CATV tuner 108and the TS decoder 109 to acquire the MPEG2 stream of the requestedcontent from the TS that is transmitted in response to the viewingrequest message, and controls the switch 102 and the MPEG2 decoder 110to play back the content.

The CPU 105 achieves functions of the recordation judging unit 111 andthe available-period monitoring unit 112 by reading a computer programstored in a ROM or a hard disk and running the read computer program,thereby controlling recordation of a content.

The recordation judging unit 111 is a functional block that includes anentry information judging subunit 113, a release judging subunit 114,and a capacity judging subunit 115. When recordation of a content isrequested by a user operation or by a programmed recording schedule, therecordation judging unit 111 judges whether to record the requestedcontent and entry information to the hard disk 104. When judging withthe entry information judging subunit 113, the release judging subunit114, and the capacity judging subunit 115 to record the requestedcontent, the recordation judging unit 111 controls the switch 102 torecord the content to the hard disk 104. On the other hand, when judgingnot to record the requested content, the recordation judging unit 111instructs the entry information recording unit 106 to record the entryinformation to the hard disk 104.

The entry information judging subunit 113 receives information from theentry information recording unit 106 as to whether each of the contentID, release date/time information, and expiry date/time information hasbeen acquired. When received information shows that the content ID isnot acquired, the entry information judging subunit 113 judges to recordthe content. When informed that the content ID is acquired but therelease date/time information and/or the expiry date/time information isnot acquired, the entry information judging subunit 113 instructs therequesting unit 107 to request for acquisition of the entry information.

When the entry information judging subunit 113 judges not to record thecontent, the capacity judging subunit 115 compares the storage spacethat is required to record the content with the available capacity, i.e.the free storage space, of the hard disk 104. When the free storagespace is greater, the capacity judging subunit 115 judges to record thecontent. On the other hand, when the free storage space falls short, thecapacity judging subunit 115 judges not to record the content.

Note that the storage space required for recording a content may becalculated precisely by using the user programmed recording hours andthe bit rate of the content or by using a rough estimate. For example,when the content is of high image quality, such as so-called HDTV (HighDefinition Television) broadcasting, it may be roughly estimated thatone-hour content requires approximately 5 gigabytes. When therecordation of the content is instructed by a user operation in realtime and thus the recording hours are not yet known, the judgment may bemade based on the storage space required for recording the content for apredetermined recording hours (for example, two hours).

When the capacity judging subunit 115 judges to record the entryinformation, the release judging subunit 114 compares the releasedate/time shown in the entry information with the current date/time.When the release date/time has not yet reached, the release judgingsubunit 114 judges to record the content to the hard disk 104 inaddition to the entry information.

The available-period monitoring unit 112 is composed of a releasedate/time monitoring subunit 116 and the expiry date/time monitoringsubunit 117. When entry information is once stored to the hard disk 104,the available-period monitoring unit 112 manages storage of the contentand the entry information based on the release and expiry dates/timesshown in the entry information so as to ensure the content is alwaysavailable for viewing.

The release date/time monitoring subunit 116 operates when the releasejudging subunit 114 judges that the release date/time has not yetreached and thus both the entry information and the content are recordedin the hard disk 104. In this case, the release date/time monitoringsubunit 116 monitors the date/time so as to control the hard disk 104 todelete the content at the time when the release date/time is reached.

The expiry date/time monitoring subunit 117 operates when entryinformation is stored alone in the hard disk 104 without a content. Inthis case, the expiry date/time monitoring subunit 117 monitors thedate/time so as to control the requesting unit 107 to issue adistribution request for the content identified by the entry informationwhen it is a predetermined time period (for example, a time period takenfor transmission of the content) until the expiry date/time. The expirydate/time monitoring subunit 117 also controls the switch 102 to recordthe content that is distributed in response to the distribution requestto the hard disk 104.

With the structure stated above, on receiving broadcasting of a contentand attached entry information, the recording apparatus stores entryinformation without the content, and later receives on-demanddistribution of the content using the recorded entry information.Consequently, the user of the recording apparatus is allowed to view thesame content as the broadcast content anytime after the broadcasting.

That is to say, the recording apparatus is advantageous in saving asignificant amount of the hard disk storage space in comparison with thecase where every one of broadcast contents is stored. As a result, agreater number of contents may be stored in the hard disk increases. Inother words, the recording apparatus is capable of storing an equalnumber of contents in a smaller capacity hard disk than in aconventional recording apparatus, which achieves an effect of reducingthe cost of the recording apparatus.

Further, the recording apparatus according to the embodiment 1 stores acontent in addition to entry information during the time between thebroadcast date/time and the release date/time, so that the user isallowed to view the content any time he desires. In addition, therecording apparatus deletes the content from the hard disk after therelease date/time, which saves storage space that would otherwise bekept occupied by the content.

Still further, the recording apparatus receives on-demand distributionof the content prior to expiry of the on-demand service for the content,and records the received content to the hard disk. Consequently, such anevent is avoided that the user can not view the content because thecontent is no longer available for on-demand distribution.

Note that the broadcast recording system 1 according to the embodiment 1is described by way of the example in which one MPEG2 stream and a pieceentry information is multiplexed to a TS. Yet, it is also applicablethat a plurality of MPEG2 streams and corresponding pieces of entryinformation are all multiplexed to a TS stream. In this case, therecording apparatus stores the plurality of pieces of entry information.

One example is found in the case of recording a so-called multi-viewtype broadcast program, which is a TS into which a plurality ofmutually-linked MPEG2 streams are multiplexed. Conventionally, whenreceiving such a multi-view type program, a recording apparatus is onlycapable of recording a main MPEG2 stream, so that the other MPEG2streams are padded with null packets without being recorded. Naturally,the user can not view the contents of which MPEG2 streams are notrecorded.

Unlike the conventional apparatus, when receiving a TS into which aplurality of MPEG2 streams and corresponding pieces of entry informationare multiplexed, the recording apparatus of the present invention storeseach piece of entry information corresponding to the MPEG2 streams otherthan the main MPEG2 stream. The pieces of entry information are storedinto a storage area that is conventionally padded with null packets.With this arrangement, the recording apparatus of the present inventionallows the user to view every content provided in the multi-viewprogram.

Operations

Next, description is given to operations of the broadcast recordingsystem 1 having the above structure.

1.4 Operations for Broadcasting Contents

FIG. 8 is a view showing the flow of operations performed by thebroadcast recording system 1 according to the embodiment 1 forbroadcasting a content through the broadcast service.

First, in order to check whether a content targeted to be broadcast willbe available for on-demand distribution, the distribution checkingsubunit 16 of the broadcasting apparatus 11 informs the broadcastdate/time of the target content to the distribution informationpresenting unit 24 of the distributing apparatus 12 (step S11).

On receiving the information regarding the broadcast date/time, thedistribution information presenting unit 24 searches the distributioninformation table stored in the distribution content accumulating unit23 for distribution information that contains a broadcast date/timematching the received broadcast date/time. When such distributioninformation is not found (S12: No), the distribution informationpresenting unit 24 informs the distribution checking subunit 16 that thetarget content is not be available for on-demand distribution (S13). Onthe other hand, when such distribution information is found in thedistribution information table, the distribution information presentingunit 24 outputs the content ID, release date/time, and expiry date/timeshown in the distribution information to the distribution checkingsubunit 16, thereby informing that the target content is available foron-demand distribution (S14).

When informed that the target content is available for on-demanddistribution (S15: Yes), the information generating subunit 17 generatesentry information from the content ID, release date/time, and expirydate/time received by the distribution checking subunit 16 from thedistribution information presenting unit 24. Subsequently, themultiplexing subunit 18 generates a TS by multiplexing the generatedentry information with an MPEG2 stream of the target content that isstored in the broadcast content accumulating unit 13 (S16). Here, in thecase where the target content has been already available for on-demanddistribution and thus the release date/time is not set, or where theexpiry date/time is not specified, the information generating subunit 17uses the default value “0XFFFFFFFFFFFF” indicating that thecorresponding information item is not set, as in the release date/timeshown in FIG. 17C. Further, in the case where the distribution checkingsubunit 16 fails to acquire a release date/time or expiry date/timehaving a valid value, the information generating subunit 17 generatesentry information without setting any value for a correspondinginformation item.

On the other hand, when informed that the target content is notavailable for on-demand distribution (S15: No), the multiplexing subunit18 generate a TS by multiplexing the MPEG2 stream of the target contentstored in the broadcast content accumulating unit 13 (S17).

The sending unit 15 broadcasts the TS generated by the multiplexingsubunit 18 via the CATV cable at a scheduled time according to thebroadcast timetable (S18).

Through the above operations, when a content identical to a targetcontent to be broadcast will be available for on-demand distribution,the broadcasting apparatus broadcasts entry information by attaching theentry information to the content. The entry information is used toidentify a content corresponding to the target broadcast content out ofa plurality of contents available for on-demand distribution.

1.5 Operations by Recording Apparatus 30 for Recording Content

Next, operations performed by the recording apparatus 30 for receiving acontent and for recording the content to the hard disk for time-shiftviewing.

FIG. 9 is a view showing the flow of operations performed by thebroadcast recording system 1 according to the embodiment 1 for recordinga content that is broadcast through the broadcast service.

When recordation of a content is requested by a user operation or by aprogrammed recording schedule (S21), the CATV tuner 108 extracts a TS ona user requested channel from signals received via the CATV cable. TheTS decoder 109 then demultiplexes the extracted TS into an MPEG2 streamand a data stream, and outputs the MPEG2 stream to the switch 102 andthe data stream to the entry information recording unit 106 (S22).

The entry information recording unit 106 attempts to acquire a contentID, a release date/time, an expiry date/time from the data stream, andinforms the recordation judging unit 111 of acquired information items(S23).

When informed that the entry information recording unit 106 fails toacquire a content ID (S23: No), the entry information judging subunit113 of the recordation judging unit 111 judges that the content is notavailable for on-demand distribution, and thus controls the switch 102to record the MPEG2 stream to the hard disk (S24). This operationcompletes the recordation of the content.

When informed that the content ID is acquired (S23: Yes), the entryinformation judging subunit 113 is further informed by the entryinformation recording unit 106 as to whether the release date/time andthe expiry date/time are acquired from the data stream (S25).

In the case where the entry information recording unit 106 fails toacquire the expiry date/time as in the example shown in FIG. 7C, therecordation judging unit 111 is informed that either, or possibly both,of the release date/time and the expiry date/time is not acquired (S25:No). In this case, the entry information judging subunit 113 instructsthe requesting unit 107 to transmit an additional informationacquisition message which serves as an acquisition request for the entryinformation (S26).

In response to the additional information acquisition message from therequesting unit 107, the distributing apparatus 12 transmits a TS thatincludes the release date/time and expiry date/time of the contentidentified by the transmitted content ID. Subsequently, the CATV tuner108 receives the TS, the TS decoder 109 demultiplexes the TS so as toseparate a data stream that includes the release date/time and expirydate/time.

The release date/time acquiring subunit 119 and the expiry date/timeacquiring subunit 120 extracts the release date/time and the expirydate/time from the data stream, respectively. Subsequently, the entryinformation recording unit 106 generates entry information, and theoperations thereafter are continued (S27).

When informed that the release date/time and the expiry date/time areacquired (S25: Yes), the capacity judging subunit 115 of the recordationjudging unit 111 compares the storage space required to store therequested content and the free storage space remaining in the hard disk104. When the free storage space falls short (S31, No), the capacityjudging subunit 115 instructs the entry information recording unit 106to record the entry information (S28).

On the other hand, the free storage space is greater (Yes), the capacityjudging subunit 115 controls the switch 102 to store the MPEG2 stream tothe hard disk 104 (S32). There may be a case where the broadcastinghours of the content being recorded is longer than estimated, and thusthe hard disk 104 runs out of the free storage space in the middle ofthe recordation process (S33: No) In that case, the recordation judgingunit 111 instructs the entry information recording unit 106 to store therecordation information (S34).

Through the above operations, the recording apparatus records entryinformation instead of the MPEG2 stream, which serves to reduce requiredstorage space of the hard disk 104.

Further, even when the hard disk 104 does not have enough free space tostore the MPEG2 stream, the recording apparatus records the entryinformation, which is significantly smaller in size than the MPEG2stream, to the hard disk 104. At a later time, the recording apparatuscan receive on-demand distribution of the content for the user to view.

Further, the recording apparatus records the MPEG2 stream to the harddisk 104 when enough free space is left, which helps to reduce trafficbetween the distributing apparatus and the recording apparatus resultingfrom a viewing request that would be made otherwise.

Further, in the case where any information item (such as a releasedate/time and an expiry date/time) is missing in the entry informationacquired with the broadcast content, the recording apparatus issues tothe distributing apparatus, a distribution request for the entryinformation, which ensures to receive the entry information. Since thedistributing apparatus uses the entry information for on-demanddistribution, the recording apparatus can reliably receive entryinformation by issuing an additional information acquisition message.With the entry information being reliably received, the recordingapparatus is allowed to collectively manage all the contents that areavailable for on-demand distribution by the distributing apparatus basedon the content IDs, the release dates/times and the expiry dates/times.

Next, description is given to another example of operations performed bythe content recording apparatus 30 to record a content.

In the operation flow shown in FIG. 9, the recording apparatus 30records the content in form of MPEG2 stream to the hard disk 104 whenthere enough free storage space left in the hard disk 104. FIG. 10 showsdifferent operations to further save the storage space of the hard disk104.

FIG. 10 is a view showing the flow of another example of operationsperformed by the broadcast recording system 1 according to theembodiment 1 for recording a content that is provided through thebroadcast service. The operations shown in FIG. 10 differ from the onesshown in FIG. 9 in that the steps S31-S34 are removed, and steps S29 andS30 are added.

The following describes the operations different from the ones shown inFIG. 9.

When informed in the step S25 that the release date/time and the expirydate/time are both acquired (S25: Yes), the recordation judging unit 111unconditionally instructs the entry information recording unit 106 torecord the entry information to the hard disk 104 (S28).

Further, when the release date/time is not yet arrived at the time ofrecording the entry information (S29: Yes), the recordation judging unit111 controls the switch 102 to record the MPEG2 stream to the hard disk104, additionally to the entry information having been already recorded(S30).

Through the above operations, the recording apparatus 30 always recordsentry information when duly receiving the entry information along withthe MPEG2 stream of the content. Consequently, the storage space of thehard disk 104 is saved significantly, which enables to record a graternumber of contents.

Further, the recording apparatus records a broadcast content in additionto the recordation information when the release date/time is not yetarrived and thus a corresponding content is not yet available foron-demand distribution at the time of recording. Consequently,time-shift viewing of the content is possible even before the releasedate/time.

1.6 Operations for Recordation Management by Recording Apparatus 30

It should be noted that a content identical to a broadcast content isnot available for on-demand distribution at all times. That is to say,in the case where the user requests to view a content some time afterrecording the content to the hard disk 104, the requested content maynot be viewed as a result of that the on-demand service no longerprovides the requested content. In order to avoid such an undesirablecase, the recording apparatus 30 of the embodiment 1 collectivelymanages all the pieces of entry information based on the releasedates/times and expiry dates/times.

FIG. 11 is a view showing the flow of operations performed by therecording apparatus 30 of the embodiment 1 for managing recordedcontents.

The following describes the operations performed by the recordingapparatus 30 to mange recorded contents.

The release date/time monitoring subunit 116 of the available-periodmonitoring unit 112 compares the current date/time with the releasedate/time shown by entry information that is recorded in the hard disk104. When the release date/time is reached (S41: Yes), the releasedate/time monitoring subunit 116 deletes the MPEG2 stream thatcorresponds to the entry information (S42).

Further, the expiry date/time monitoring subunit 117 of theavailable-period monitoring unit 112 compares the current date/time withthe expiry date/time shown by entry information that is recorded in thehard disk 104. When it is a predetermined time period until the expirydate/time (for example, the predetermine time period is a time periodtaken for transmission of the content) (S43, Yes), the available-periodmonitoring unit 112 instructs the requesting unit 107 to issue a requestfor distribution of the content identified by the entry information(S44). In addition, the available-period monitoring unit 112 instructsthe CATV tuner 108, the TS decoder 109, and the switch 102 to record anMPEG2 stream distributed in response to the distribution request (S45).

Through the above operations, in the case of receiving and recordingentry information and an MPEG2 stream before the release date/time, therecording apparatus 30 deletes the MPEG2 stream when the releasedate/time comes. Consequently, the storage space of the hard disk 104 issaved.

Further, in the case where a content has an expiry date/time for theon-demand distribution, the recording apparatus 30 acquires the contentfrom the distributing apparatus prior to the expiry date/time andrecords the acquired content to the hard disk. Consequently, it isensured that the user can view playback of the content at any desiredtime.

1.7 Playback Operations Performed by Recording Apparatus

Next, description is given to operations performed by the recordingapparatus 30 of the embodiment 1 for the user to view a recordedcontent.

FIG. 12 is a view showing the flow of operations performed by therecording apparatus 30 of the embodiment 1 when the user views arecorded content.

When playback of a content is requested by a user operation (S51), theCPU 105 judges whether an MPEG stream of the requested content isrecorded in the hard disk 104. Judging that the MPEG2 stream of thecontent is recorded in the hard disk 104 (S52: Yes), the CPU 105controls the switch 102 and the output unit 103 to read the MPEG2 streamand display the read MPEG2 stream on the television set (S53).

On the other hand, when the MPEG2 stream of the requested content is notrecorded in the hard disk 104 (S52: No), the requesting unit 107generates a viewing request message using the content ID that is shownby the entry information of the requested content, and transmits theviewing request message to the distributing apparatus 12 via the CATVcable (S54). Then, the receiving unit 101 receives an MPEG2 stream thatis on-demand distributed in response to the viewing request message, andthe CPU 105 controls the switch 102 and the output unit 103 to displaythe received MPEG2 stream on the television set (S55).

Through the above operations, the recording apparatus 30 of theembodiment 1 ensures that a broadcast content can be played back anytimeafter the broadcasting regardless of whether the hard disk 104 stores anMPEG2 stream of the content or entry information of the content withoutthe MPEG2 stream.

Embodiment 2

Overview

Hereinafter, description is given to a broadcast recording system 2according to an embodiment 2 of the present invention. The broadcastrecording system 2 provides a broadcast service by way of terrestrialanalog broadcasting, and an on-demand service via the Internet.

Structure

2.1 System Configuration

FIG. 13 is a view showing the configuration of the broadcast recordingsystem 2 according to the embodiment 2 of the present invention.

The broadcast recording system 2 is composed of a television broadcaststation 40, a recording apparatus 50, and a content distribution centers60 and 70. According to the broadcast recording system 2, the televisionbroadcast station 40 broadcasts contents, and the recording apparatus 50receives and records the contents. The television broadcast station 40,the recording apparatus 50, and the content distribution centers 60 and70 are mutually connected via the Internet.

The television broadcast station 40 broadcasts contents based on theNTSC standard according to a predetermined broadcast timetable.

Each of the content distribution centers 60 and 70 is a so-called ISP(Internet Service Provider), for example, and accumulates contents eachidentical to a content broadcast through the broadcast service, anddistributes accumulated contents on-demand to a recording apparatusowned by a subscriber via the Internet.

The recording apparatus 50 receives and records contents broadcast fromthe television broadcast station 40 through the broadcast service. Inaddition, the recording apparatus 50 requests the distribution centers60 and 70 to distribute contents, and receives distributed contents viathe Internet.

2.2 Television Broadcast Station 40

Hereinafter, description is given to the detailed structure of thetelevision broadcast station 40.

FIG. 14 is a view showing the structures of the broadcast station 40 andthe content distribution center 60 according to the embodiment 2 of thepresent invention.

The television broadcast station 40 includes a broadcast contentaccumulating unit 41, an adding unit 42, and a transmitting unit 43, andbroadcasts contents based on the NTSC standard at scheduled timesaccording to the predetermined broadcast timetable. When broadcasting acontent to which an identical content is allowed to be distributed bythe content distribution center 60 or 70, the television broadcaststation 40 superimposes to the broadcast wave, entry information thatincludes a URL (Uniform Resource Locator) showing a storage location ofthe content on the Internet.

The broadcast content accumulating unit 41 accumulates contents to bebroadcast through the, broadcast service, and outputs an NTSC signalrepresenting a content at the time of broadcasting.

The adding unit 42 includes functional blocks of a distribution checkingsubunit 44, an information generating subunit 45, and a superimposingsubunit 46. To broadcast a content to which an identical content isavailable for on-demand distribution, the adding unit 42 superimposescorresponding entry information onto a broadcast wave carrying thecontent to be broadcast.

The distribution checking subunit 44 transmits to the contentdistribution centers 60 and 70, a broadcast date/time of the content tobe broadcast, and receives information as to whether an identicalcontent is available for on-demand distribution. When the distributioninformation presenting unit 63 informs that the identical content isavailable for on-demand distribution, the distribution checking subunit44 acquires from the distribution information presenting unit 63, a URLshowing a storage location of the distribution content, and qualityinformation composed of resolution and bit rate of the distributioncontent, and outputs the acquired information to the informationgenerating subunit 45.

The information generating subunit 45 generates entry information shownin FIG. 15 using the information outputted from the distributionchecking subunit 44.

When broadcasting a content to which an identical content is availablefor on-demand distribution, the superimposing subunit 46 superimposesentry information generated by the information generating subunit 45 toan NTSC signal that is outputted from the broadcast content accumulatingunit 41 for the transmitting unit 43 to broadcast.

The transmitting unit 43 broadcasts the NTSC signal outputted from thesuperimposing subunit 46 at scheduled times according to the broadcasttable.

FIG. 15 is a view showing the data structures of entry informationaccording to the embodiment 2 and of an NTSC signal 401 in to which theentry information is superimposed.

The NTSC signal 401 corresponds to one frame, and a data stream 402 issuperimposed into a part of the vertical blanking period. The datastream402 contains a data header 403 and entry information that is composed ofa URL 404 and quality information 405.

The URL 404 shows a storage location of a distribution content on theInternet, and the quality information 405 shows the resolution and bitrate at which the content is distributed.

The entry information is superimposed to each frame of the content. Thatis to say, the entry information may be acquired any time duringbroadcasting of the content.

The technique to superimpose a data stream into a vertical blankingperiod of an NTSC signal is well known in the art employed for examplein character broadcasting, and thus detailed description thereof isomitted.

With the above structure, when broadcasting a content to which anidentical content is available for on-demand distribution, thetelevision broadcast station 40 broadcasts entry information bysuperimposing the entry information into an NTSC signal carrying thecontent.

2.3 Content Distribution Center 60

Next, description is given to the detailed structure of the contentdistribution center 60.

The content distribution center 60 is composed of a content distributingunit 61, a distribution content accumulating unit 62, a distributioninformation presenting unit 63, a transfer information storing unit 64,and a distribution request transferring unit 65.

The content distribution center 60 prepares a plurality of MPEG2 streamsfor one content with different image qualities, i.e. differentresolutions and bit rates, and thus capable of providing a suitablevideo content depending on the resolution of the recording apparatus towhich the content is distributed or the bit rate of the communicationline via which the content is distributed.

The content distributing unit 61 receives from the recording apparatus50, a viewing request packet shown in FIG. 16, and reads a requestedcontent from the distribution content accumulating unit 62, anddistributes the read content to the request source, i.e. the recordingapparatus 50. In the case where the content requested by the viewingrequest packet is not stored in the distribution content accumulatingunit 62, the content distributing unit 61 informs the distributionrequest transferring unit 65 that the requested content is not found.

The distribution content accumulating unit 62 is a large-capacityrecording device storing distribution contents in MPEG2 streams. To bemore specific, the distribution content accumulating unit 62 stores aplurality of MPEG2 streams for one content with different imagequalities such as resolutions and bit rates. The distribution contentaccumulating unit 62 further stores, for each of the stored contents,distribution information composed of a broadcast date/time, an URL, andquality information of a highest image quality MPEG2 stream among allthe MPEG2 streams of a corresponding content.

The distribution information presenting unit 63 receives from thetelevision broadcast station 40, a broadcast date/time of a content tobe broadcast, and searches the distribution content accumulating unit 62for distribution information showing a matching broadcast date/time.When there is matching distribution information, the distributioninformation presenting unit 63 transmits a URL and quality informationthat is included in the distribution information to the distributionchecking subunit 44 of the television broadcast station 40, therebyinforming that the content to be broadcast is available for on-demanddistribution.

There may be a case where a content stored in the distributionaccumulating unit 62 is transferred to another content distributioncenter by the administrator of the content distribution center 60 inorder to secure the available storage capacity or because the expirydate/time of the content is passed. The transfer information storingunit 64 stores a URL of a location to which a content is transferred. Tobe more specific, the transfer information storing unit 64 stores, foreach content transferred, a URL of a content distribution center towhich being a destination of transmission or transfer or of a proxyserver to which a copy of the content is cached.

When receiving information from the content distributing unit 61 thatthe requested content is not found, the distribution requesttransferring unit 65 retrieves a URL showing a transfer destination ofthe requested content from the transfer information storing unit 64, andtransfers the viewing request packet to the retrieved URL via theInternet, thereby requesting to transmit the requested content to thedistributing apparatus 50.

With the above structure, the content distribution center 60 transmitsthe requested content to the recording apparatus 50.

Note that the content distribution center 70 has a similar structure tothat of the content distribution center 60.

2.4 Recording Apparatus 50

Next, description is given to the structure of the recording apparatus50.

FIG. 17 is a view showing the structure of the recording apparatus 50according to the embodiment 2 of the present invention.

The recording apparatus 50 is composed of a receiving unit 201, a switch102, an output unit 103, a hard disk 104, a CPU 105, an entryinformation recording unit 202, and a requesting unit 203.

Note that those components denoted by the same reference numerals as inthe recording apparatus 30 are similar to the corresponding components,and thus description thereof is omitted.

The receiving unit 201 is a functional block for receiving a contentbroadcast or distributed from the television broadcast station 40, orthe content distribution center 60 or 70. Specifically, the receivingunit 201 is composed of a television tuner 204, a demultiplexer 205, anMPEG2 encoder 206, and demodulator 207.

The television tuner 204 receives a broadcast wave from the televisionbroadcast station 40, and tunes to a user selected channel to output anNTSC signal received on the channel.

The demultiplexer 205 extracts a data stream from the NTSC signalcorresponding to the vertical blanking period and outputs the extracteddata stream to the entry information recording unit 202.

The MPEG2 encoder 206 encodes the NTSC signal to an MPEG2 stream incompliance with the MPEG2 standard, and outputs the resulting MPEG2stream to the switch 102.

The demodulator 207 is connected to a downstream of the Internet, andextracts an MPEG2 stream from input packets received via the Internet,and outputs the MPEG2 stream to the switch 102.

The entry information recording unit 202 includes a URL acquiringsubunit 208 and a quality information acquiring subunit 209. The URLacquiring subunit 208 extracts a URL showing a storage location of acontent from the data stream that is demultiplexed from the receivedNTSC signal, and the quality information acquiring subunit 209 extractsquality information that is composed of a resolution and a bit rate ofthe content. With the above operations, the entry information recordingunit 202 acquires entry information.

Further, the entry information recording unit 202 informs therecordation judging unit 212 as to whether each of the URL and thequality information has been acquired. Further, in response to arecordation instruction from the recordation judging unit 212, the entryinformation recording unit 202 records the entry information to the harddisk 104.

The requesting unit 203 is composed of a request generating subunit 210and a modulator 211, and issues to the content distribution center 60, arequest for on-demand distribution of a content.

The requesting unit 203 issues such a distribution request based on theresolution and the bit rate shown in the entry information that acontent is to be distributed at bit rate and resolution suitable to therecording apparatus 50. Consequently, it is ensured that the user canview playback of the content without frame skips or playback ratefluctuations. In addition, the user may view a content that is playedback at a higher bit rate and higher image quality than a correspondingbroadcast content.

To play back a content that is not stored in the hard disk 104 althoughcorresponding entry information is stored, the request generatingsubunit 210 generates a viewing request packet shown in FIG. 16 undercontrol by the CPU 105. The viewing request packet is generated withreference to the entry information that is read from the hard disk 104and the resolutions and bit rates that the recording apparatus 50 isprovided for. The request generating subunit 210 then outputs thegenerated viewing request packet to the modulator 211.

The modulator 211 modulates the viewing request packet into a packetsuitable for output, and then outputs the output packet to an upstreamof the Internet.

The CPU 105 controls playback of a content in a similar manner to theembodiment 1.

Further, the CPU 105 performs the function of the recordation judgingunit 212 by executing a computer program stored for example in a ROM ora hard disk, thereby controlling recordation of cornets.

The recordation judging unit 212 is a functional block that includes anentry information judging subunit 213, a quality judging subunit 214,and a capacity judging subunit 215, and judges, when recordation of acontent is requested by a user operation or by a programmed recordingschedule, whether to record the requested content and correspondingentry information to the hard disk 104. When the entry informationjudging subunit 213, the quality judging subunit 214, and the capacityjudging subunit 215 judge to record the requested content, therecordation judging unit 212 controls the switch 102 to record thecontent to the hard disk 104. On the other hand, when it is judged torecord the entry information, the recordation judging unit 212 instructsthe entry information recording unit 202 to record the entry informationto the hard disk 104.

The entry information judging subunit 213 receives information from theentry information recording unit 202 as to whether each of the URL andthe quality information is acquired. When informed that the URL is notacquired, the entry information judging subunit 213 judges to record thecontent.

The capacity judging subunit 215 is a functional block that is similarto the capacity judging subunit 115 of the embodiment 1.

The quality judging subunit 214 compares, when the capacity judgingsubunit 215 judges to record the content, the image quality of thereceived content (meaning, in the embodiment 2, the MPEG2 streamgenerated by encoding the NTSC signal) with the image quality shown bythe quality information. When the image quality shown by the qualityinformation is higher, the quality judging subunit 214 overrides thejudgment of the capacity judging subunit 215 so that entry informationis to be stored instead of the content.

With the above structure, when the hard disk 104 does not have enoughfree storage space to record a content, the recording apparatus recordsentry information of the content. Since the entry information isrecorded, the recording apparatus is allowed to receive a content thatis identical to the broadcast content, so that the user can view thedistributed content at a later time.

Consequently, the storage space of the hard disk is significantly savedin comparison with storing all the contents broadcast.

Further, the recording apparatus compares image qualities of a broadcastcontent and a content to be on-demand distributed shown by entryinformation that is acquired along with the broadcast content, andselects a content that is better in image quality.

Consequently, the user is allowed to view a content that is better inimage quality.

Further, in the case where a plurality of, concurrently broadcastcontents are requested to be recorded by the user or by a programmedrecording schedule, the CPU 105 controls each functional block asfollows. First, the television tuner 204 is controlled to select achannel on which a first content is broadcast and acquire an NTSC signalbroadcast on the channel. The entry information recording unit 202 iscontrolled to acquire entry information from the NTSC signal and recordthe acquired entry information to the hard disk 104. The CPU 105 thencontrols the television tuner 204 to switch to a channel on which asecond content is broadcast, and to acquire an NTSC signal broadcast onthe channel. The entry information recording unit 202 is then controlledto acquire entry information from the NTSC signal, and record theacquired entry information to the hard disk 104. The CPU 105 furtherperforms similar control to record entry information of a third contentand thereafter.

As described above, when a plurality of concurrently broadcast contentsare requested to be recorded, the recording apparatus sequentiallyrecords entry information of each content instead of MPEG2 streams. Withthis arrangement, the recording apparatus allows the user to view all ofthe requested contents at a later date.

Operations

Next, description is given to the flow of operations performed by thebroadcast recording system 2 having the above structure.

2.5 Recordation Operations Performed by Recording Apparatus 50

Now, description is given to operations performed by the recordingapparatus 50 for receiving a content and recording the content to thehard disk for the purpose of time-shift viewing.

FIG. 18 is a view showing the flow of operations performed by thebroadcast recording system 2 according to the embodiment 2 of thepresent invention for recording a content that is provided through thebroadcast service.

When recordation of a content is requested by a user operation or by aprogrammed recording schedule (S61), the television tuner 204 selects anNTSC signal on a user selected channel from among all the signalsreceived with the antenna, and outputs the selected signal to thedemultiplexer 205 and the MPEG2 encoder 206 (S62).

The MPEG2 encoder 206 extracts video and audio data from the NTSCsignal, converts the extracted data to an MPEG2 stream, and outputs theresulting MPEG2 stream to the switch 102.

The demultiplexer 205 separates a data stream that is superimposed tothe NTSC signal corresponding to a vertical blanking period, and outputsthe data stream to the entry information recording unit 202. The entryinformation recording unit 202 attempts to acquire a URL and qualityinformation with the URL acquiring subunit 208 and the qualityinformation acquiring subunit 209. The entry information recording unit202 then informs the recordation judging unit 212 as to whether eachinformation item is acquired.

When informed by the entry information recordation unit 202 that the URLis not acquired (S63: No), the entry information judging subunit 213 ofthe recordation judging unit 212 judges that a content corresponding tothe requested content is not available for on-demand distribution, andthus controls the switch 102 to record the MPEG2 stream to the hard disk104 (S64), and completes the recordation.

On the other hand, when informed that the URL is acquired (S63: Yes),the capacity judging subunit 215 of the recordation judging unit 212compares a free storage space of the hard disk 104 with a storage spacerequired to record the requested content in form of MPEG2 stream. Onjudging that the free storage space of the hard disk 104 falls short(S65), the capacity judging subunit 215 instructs the entry informationrecording unit 202 to record the entry information (S66), and completesthe recordation.

In contrast, when the free storage space of the hard disk 104 is greater(S65: Yes), the quality judging subunit 214 of the recordation judgingunit 212 then compares the image quality shown by the entry informationwith the image quality of the MPEG2 stream generated by encoding thereceived NTSC signal (S67).

On judging that the image quality shown by the entry information ishigher (S67: No), the quality judging subunit 214 instructs the entryinformation recording unit 202 to record the entry information to thehard disk 104 (S66), and completes the recordation.

On the other hand, on judging that the image quality of the MPEG2 streamis higher (S67: Yes), the quality judging subunit 214 controls theswitch 102 to record the MPEG2 stream to the hard disk 104 (S68). In thecase where the content being recorded is longer than the predeterminedtime period, the hard disk 104 runs out of the storage space in themiddle of recordation process (S69: No). In such a case, the recordationjudging unit 212 instructs the entry information recording unit 202 torecord the entry information (S70).

Through the above operations, even if enough storage space is not leftin the hard disk 104 for recording an MPEG2 stream of a broadcastcontent, the recording apparatus 50 records, instead of MPEG2 stream,entry information acquired from the received NTSC signal. Since theentry information is recorded, the recording apparatus 50 is allowed toreceive on-demand distribution of the content, so that the user can viewthe content at a later time.

Further, in the case where a content is programmed in advance by a userto be recorded, a total record time is specifically known. Consequently,comparison of the free storage space of the hard disk 104 and thestorage space required for recording the content is reliably made. As aresult, such an undesirable occurrence is eliminated that the content isrecorded only halfway through due to the shortage of the availablememory of the hard disk 104.

In the case where a total record time is not surely known before actualrecording, it is possible that the hard disk 104 runs out of the freestorage space halfway through the recordation process. In such a case,however, the recording apparatus records entry information, which issignificantly smaller in size than the content. As long as the entryinformation is recorded, the recording apparatus is allowed to receivean identical content provided through the on-demand distributionservice. This leads to eliminate undesirable possibility that the usercan not view the content through to the end.

Further, the recording apparatus compares, using entry informationacquired with a content provided through the broadcast service, imagequalities of the broadcast content and of an on-demand distributioncontent. When the broadcast content is better in image quality, therecording apparatus records the content that is acquired from thereceived broadcast wave. On the other hand, when the distributioncontent is better in image quality, the recording apparatus recordsentry information that is acquired from the received broadcast wave.Consequently, the user is allowed to view at a later date, whichevercontent is better in the image quality.

2.6 Operations by Content Distribution Centers 60 and 70 for ContentDistribution

Now, description is given to operations performed by the contentdistribution centers 60 and 70 for distributing a content.

FIG. 19 is a view showing the flow of the operations performed by thebroadcast recording system 2 according to the embodiment 2 of thepresent invention to provide a content through the on-demanddistribution service.

A viewing request packet transmitted from the recording apparatus 50 isdelivered via the Internet to the content distribution center 60 that isspecified by the URL as a transmission destination (step S71).

When the content distribution center 60 receives the viewing requestpacket, the content distributing unit 61 searches all the MPEG2 streamsstored in the distribution content accumulating unit 62 for an MPEG2stream that is specified by the URL included in the viewing requestpacket.

When the distribution content accumulating unit 62 stores the specifiedMPEG2 stream (S72: Yes), the content distributing unit 61 acquires theMPEG2 stream from the distribution content accumulating unit 62, andtransmits the acquired MPEG2 stream to the recording apparatus 50 viathe Internet (S73).

There may be a case where an administrator of the content distributioncenter 60 transfers a content stored in the distribution contentaccumulating unit 62 to another content distribution center (forexample, the content distribution center 70) in order to secure thestorage space of the distribution content accumulating unit 62. That isto say, there may be a case where the distribution content accumulatingunit 62 no longer stores the specified content (step S72: No). In thatcase, the content distributing unit 61 informs the distribution requesttransferring unit 65 that the MPEG2 stream of the requested content isnot acquired.

In response, the distribution request transferring unit 65 searches thetransfer information storing unit 64 to judge whether a transferdestination of the requested content is stored. When the transferdestination of the requested content is not found (S74: No), thedistribution request transferring unit 65 informs the recordingapparatus 50, which is the transmission source of the viewing requestpacket, that the requested content is not available (S75).

On the other hand, when the transfer destination of the requestedcontent is found in the transfer information storing unit 64 (S74: Yes),the distribution request transferring unit 65 transfers the viewingrequest packet to the URL of the transfer destination (for example, thecontent distribution center 70) via the Internet, thereby requesting todistribute the requested content to the recording apparatus 50 (S76).

On receiving the viewing request packet transferred from the contentdistribution center 60 (S77), the content distribution center 70operates as follows. First, the content distributing unit acquires anMPEG2 stream of the requested content from the content accumulatingunit, and then transmits the MPEG2 stream to the recording apparatus 50,which is the request source (S78).

Through the above operations, the content distribution center is able toprovide a content requested by the recording apparatus even if therequested content is not stored within the distribution center.

Consequently, when the recording apparatus stores entry informationwithout an MPEG2 stream of the content, and when the contentdistribution center to which the recording apparatus made a distributionrequest no longer stores the requested content, it is still ensured thatthe user of the recording apparatus acquires the requested content andview the content.

Note that the content distribution center 70 received the viewingrequest packet may perform the similar operations to the contentdistribution center 60 (the searches for the requested content and thetransfer information), so that and the viewing request packet is furthertransferred to yet another content distribution center.

3. Modifications

Up to this point, the present invention has been described by way of theabove embodiments 1 and 2. It is naturally appreciated, however, thatthe present invention is in no way limited to those specific embodimentsand modifications such as the following are still within the scope ofthe present invention.

(1) The present invention may be embodied as the methods describedabove. Further, the present invention may be embodied as computerprograms realizing the methods by a computer, or digital signalsrepresenting the computer programs.

Further, the present invention may be embodied as a computer-readablerecording medium storing the computer programs or the digital signals.Examples of such a recording medium include a flexible disk, a harddisk, CD-ROM, MO, DVD, DVD-ROM, DVD-RAM, BD (Blu-ray Disc) and asemiconductor memory. Further, the present invention may be embodied asthe computer program or the digital signal recorded on any recordingmedium mentioned above.

Still further, the present invention may be embodied as the computerprograms or the digital signals transmitted via an electriccommunication line, wireless communications, a wired communication line,or a network typified by the Internet.

Still further, the present invention may be embodied as a computersystem composed of a microprocessor and memory. The memory stores thecomputer programs mentioned above, and the microprocessor may operateaccording to the computer programs.

Still further, the programs or the digital signals may be transferred inform of a recording medium mentioned above, or via a network mentionedabove, so that the programs or the digital signals may be executed byanother independent computer system.

(2) The entry information according to the present invention does notnecessarily have the data structure described in the above embodiments 1and 2. Any other data structure is applicable as long as the informationuniquely specifies a corresponding content for on-demand distribution.

For example, the entry information may specify a content by the channeland the date/time on which the content is broadcast. In this case, thedistributing apparatus stores a table in which each content foron-demand distribution is correlated with a corresponding broadcastingchannel and broadcast date/time. Consequently, the recording apparatusmay make a distribution request using the broadcasting channel andbroadcast date/time of a desired content.

(3) The broadcasting apparatus according to the present invention maybroadcast contents any broadcasting system other than CATV broadcastingand terrestrial analog broadcasting. For example, the broadcastingapparatus may broadcast contents by way of terrestrial digitalbroadcasting, BS broadcasting, BS digital broadcasting, or CSbroadcasting.

(4) In the above embodiments, entry information is added to a content bymultiplexing the entry information to a TS compliant with the MPEG2standard or by superimposing the entry information to analog broadcastwave in the vertical blanking period. According to the presentinvention, however, a content and entry information may togetherbroadcast by any other way. For example, entry information may bemultiplexed to a TS using a data carousel scheme, which is used indigital broadcasting for data broadcasting.

(5) In the above embodiments, an MPEG2 stream that is generated byencoding a content and entry information are both stored to the harddisk. Yet, it is not necessary to record the MPEG2 stream and the entryinformation to the same recording medium. For example, the entryinformation may be recorded to another recording medium such as RAM.

(6) In the above embodiments, the coding of contents for broadcasting,distribution, and recordation are performed all in compliance with theMPEG2 standard. Yet, the coding employed in the broadcast recordingsystem of the present invention is not limited to the MPEG2 standard andmay be any coding such as one in compliance with the MPEG4 standard, theH.263 standard, and the H.264 standard.

(7) The recording apparatus according to the present invention may be sostructured to acquire entry information attached to a broadcast contentin the middle of the broadcasting, requests the distributing apparatusto distribute a content specified by the acquired entry information, sothat the recording apparatus is allowed to play back the distributedcontent from the beginning.

With this structure, the user of the recording apparatus can viewplayback of a content from the beginning even if the user requestsrecordation of the content in the middle of the broadcasting.

(8) The recording apparatus according to the present invention mayfurther include a restricting unit to impose restrictions on recordationof broadcast contents, and the distributing apparatus may distribute acontent that is identical in substance of data but in degraded imagequality.

This arrangement prevents recordation and unlimited duplication of acontent that is broadcast in high image quality by way of digitalbroadcasting.

(9) The present invention may be any combination of the above-describedembodiment and modifications.

Industrial Applicability

The broadcast recording system according to the present inventionachieves an effect of reducing storage space used to record broadcastcontents, and thus highly applicable, for example, to a hard diskrecorder for recording broadcast contents.

1. A broadcast recording system comprising: a broadcasting apparatusthat includes an attaching unit operable to attach to a broadcastcontent that is for broadcasting and that corresponds to a specific oneof a plurality of contents each composed at least of video and audiodata, entry information specifying a distribution content that iscomposed of video and audio data and identical to the specific contentwith respect to a substance of the video and audio data out of aplurality of distribution contents available for distribution by adistributing apparatus, and a broadcasting unit operable to broadcastthe broadcast content with the attached entry information; a recordingapparatus that includes a receiving unit operable to receive thebroadcast content with the attached entry information from thebroadcasting apparatus, an entry information recording unit operable torecord the entry information attached to the received broadcast contentto a storage area, and a requesting unit operable to request thedistributing apparatus to distribute the distribution content specifiedby the recorded entry information; and the distributing apparatus thatdistributes the specified distribution content to the recordingapparatus in response to the distribution request from the requestingunit, wherein the recording apparatus receives, after broadcasting ofthe broadcast content that is identical to the specific content withrespect to the substance of the video and audio data, the distributioncontent that is identical to the specific content with respect to thesubstance of the video and audio data and plays back the receiveddistribution content.
 2. A recording apparatus comprising: a receivingunit operable to receive, from a broadcasting apparatus for broadcastingbroadcast contents each of which is for broadcasting together with entryinformation attached thereto and corresponds to a content composed atleast of video and audio data, a broadcast content that is composed ofvideo and audio data and identical to a specific one of the contentswith respect to a substance of the video and audio data together withattached entry information specifying a distribution content that iscomposed of video and audio data and identical to the specific contentwith respect to a substance of the video and audio data out of aplurality of distribution contents available for distribution by adistributing apparatus; an entry information recording unit operable torecord the entry information attached to the received broadcast contentto a storage area; and a requesting unit operable to request thedistributing apparatus to distribute the distribution content specifiedby the recorded entry information, wherein the recording apparatus playsback the distribution content distributed by the distributing apparatusin response to the distribution request.
 3. The recording apparatusaccording to claim 2, wherein the broadcast content and the distributioncontent that correspond to the specific content are all identical as acopyrighted work, and at least one of the broadcast content and thespecific content differs from the specific content with respect to animage quality.
 4. The recording apparatus according to claim 2, furthercomprising: a judging unit operable to judge whether to record thereceived broadcast content; and a content recording unit operable torecord the received broadcast content to the storage area when thejudging unit judges to record the broadcast content.
 5. The recordingapparatus according to claim 4, wherein the judging unit judges not torecord the received broadcast content when the entry information isattached, and judges to record the received broadcast content when theentry information is not attached.
 6. The recording apparatus accordingto claim 4, wherein the entry information further includes informationshowing image quality of the distribution content specified by the entryinformation, and the judging unit judges to record the receivedbroadcast content when image quality of the received broadcast contentis higher than the image quality shown by the entry information, andjudges not to record the received broadcast content when the imagequality of the received broadcast content is lower.
 7. The recordingapparatus according to claim 4, wherein the judging unit judges torecord the received broadcast content when a free storage spaceremaining in the storage area is greater than a storage space requiredfor recording the broadcast content, and judges not to record thereceived broadcast content when the free storage space is smaller. 8.The recording apparatus according to claim 4, wherein the entryinformation recording unit does not record the entry information whenthe broadcast content is judged to be recorded.
 9. The recordingapparatus according to claim 8, wherein the entry information recordingunit records to the storage area, the entry information attached thebroadcast content being recorded by the content recording unit when afree storage space of the storage area falls short to record entirety ofthe broadcast content.
 10. The recording apparatus according to claim 2,further comprising: a content recording unit operable to record thereceived broadcast content to the storage area; and a content deletingunit, wherein the entry information further includes information showinga release date-time on which the distribution content starts to beavailable for distribution, and the content deleting unit deletes thebroadcast content recorded by the content recording unit from thestorage area on or after the release date-time.
 11. The recordingapparatus according to claim 2, further comprising a content recordingunit operable to record to the storage area, the distribution contentthat is distributed by the distributing apparatus in response to thedistribution request, wherein the entry information further includesinformation showing an expiry date-time after which the distributioncontent is no longer available for distribution, and the requesting unitrequests distribution of the distribution content prior to the expirydate-time.
 12. The recording apparatus according to claim 2, furthercomprising an entry information requesting unit operable to request thedistributing apparatus to distribute the entry information when anyinformation item is missing in the entry information attached to thereceived broadcast content, wherein the entry information recording unitrecords to the storage area, the entry information that is distributedfrom the distributing apparatus in response to the request from theentry information requesting unit.
 13. The recording apparatus accordingto claim 2, wherein the receiving unit receives from the broadcastingapparatus, a broadcast content corresponding to a first content and withfirst entry information attached thereto, the first entry informationspecifying a distribution content that is composed of video and audiodata and identical to the first content with respect to a substance ofthe video and audio data, and further receives, after the entryinformation recording unit records the first entry information, abroadcast content that corresponds to a second content and that isbroadcast with second entry information attached thereto from anotherbroadcasting apparatus during the broadcasting of the broadcast contentcorresponding to the first content, the second entry informationspecifying a distribution content that is composed of video and audiodata and identical to the second content with respect to a substance ofthe video and audio data, and the entry information recording unitrecords the first entry information to the storage area when thereceiving unit receives the broadcast content to which the first entryinformation is attached, and further records the second entryinformation to the storage area when the receiving unit receives thebroadcast content to which the second entry information is attached. 14.The recording apparatus according to claim 2, wherein the broadcastingapparatus broadcasts a broadcast content multiplexed with anotherbroadcast content, one of the broadcast contents corresponding to afirst content and with first entry information attached thereto, thefirst entry information specifying a distribution content that iscomposed of video and audio data and identical to the first content withrespect to a substance of the video and audio data, and the otherbroadcast content corresponding to a second content and with secondentry information attached thereto, the second entry informationspecifying a distribution content that is composed of video and audiodata and identical to the second content with respect to a substance ofthe video and audio data, and the information recording unit records thefirst entry information and the second entry information to the storagearea.
 15. A broadcasting apparatus comprising: an attaching unitoperable to attach to a broadcast content that is for broadcasting andthat corresponds to a specific one of a plurality of contents eachcomposed of at least video and audio data, entry information specifyinga distribution content that is composed of video and audio data andidentical to the specific content with respect to a substance of thevideo and audio data out of a plurality of distribution contentsavailable for distribution by a distributing apparatus; and abroadcasting unit operable to broadcast the broadcast content with theattached entry information.
 16. The broadcasting apparatus according toclaim 15, wherein the attaching unit includes: a distribution judgingsubunit operable to judge whether the distribution content correspondingthe specific content is available for distribution by the distributingapparatus; and an entry information generating subunit operable, whenthe distribution judging subunit judges in affirmative, to generate theentry information specifying the distribution content corresponding thespecific content, and attach the generated entry information to thebroadcast content.
 17. A recording program for having a computerperform: a receiving step of receiving, from a broadcasting apparatusfor broadcasting broadcast contents each of which is for broadcastingtogether with entry information attached thereto and corresponds to acontent composed at least of video and audio data, a broadcast contentthat is composed of video and audio data and identical to a specific oneof the contents with respect to a substance of the video and audio datatogether with attached entry information specifying a distributioncontent that is composed of video and audio data and identical to thespecific content with respect to a substance of the video and audio dataout of a plurality of distribution contents available for distributionby a distributing apparatus; an entry information recording step ofrecording the entry information attached to the received broadcastcontent to a storage area; a requesting step of requesting thedistributing apparatus to distribute the distribution content specifiedby the recorded entry information; and a playback step of playing backthe distribution content distributed by the distributing apparatus inresponse to the distribution request.